Most of the explanations for the gaps have to do with the impact of marriage and childrearing on the hours men and women can put into work or the roles that married women – especially those with children – sometimes wind up in, the so-called ‘Mommy track.’ And so, the argument goes, having more equal marriages that give women the freedom to devote themselves to work will lead to more equal treatment in the workplace.

But there is a cultural component too, a set of assumptions employers make about married women, even ones who have supportive spouses doing their share of the housework or the daycare duty. And those assumptions – a new study suggests – have much to do with the home lives of the bosses themselves.

Researchers from Harvard and UNC-Chapel Hill found that men with stay-at-home wives were far more likely to discriminate against female employees, offering fewer promotions which in turn will lead to lower salaries.

That is, we found that employed husbands in traditional and neo-traditional marriages, compared to those in modern marriages, tend to (a) view the presence of women in the workplace unfavorably, (b) perceive that organizations with higher numbers of female employees are operating less smoothly, (c) find organizations with female leaders as relatively unattractive, and (d) deny, more frequently, qualified female employees opportunities for promotion.

There is an obvious reason for this: that men who live in traditional marriages are more likely to have more traditional worldviews overall and less likely to have been exposed to feminist or gender-egalitarian ideas.

The more interesting suggestion is that these men are acting out of self-interest. We know that the earnings premium for married men is highest for those whose wives don’t work outside the home, and instead provide supportive labor in the home that enables their husbands to be better employees.

And so the authors of this paper suggest that men with stay-at-home wives are enforcing in the workplace an order that they know benefits them personally, seeing the women who work for them as proxies for what their wives could become. The values these men express – that women aren’t competent at their jobs, that marriages work better when women stay home– are actually rationalizations for a self-interested reaction to a perceived threat.

Feminists have always maintained that the personal is political. It’s interesting to see data supporting it.